Add LDPT_REGISTER_CLAIM_FILE_HOOK_V2 linker plugin hook [GCC PR109128]

This is one part of the fix for GCC PR109128, along with a
corresponding GCC change.  Without this patch, what happens in the
linker, when an unused object in a .a file has offload data, is that
elf_link_is_defined_archive_symbol calls bfd_link_plugin_object_p,
which ends up calling the plugin's claim_file_handler, which then
records the object as one with offload data. That is, the linker never
decides to use the object in the first place, but use of this _p
interface (called as part of trying to decide whether to use the
object) results in the plugin deciding to use its offload data (and a
consequent mismatch in the offload data present at runtime).

The new hook allows the linker plugin to distinguish calls to
claim_file_handler that know the object is being used by the linker
(from ldmain.c:add_archive_element), from calls that don't know it's
being used by the linker (from elf_link_is_defined_archive_symbol); in
the latter case, the plugin should avoid recording the object as one
with offload data.

	bfd/
	* plugin.c (struct plugin_list_entry): Add claim_file_v2.
	(register_claim_file_v2): New.
	(try_load_plugin): Use LDPT_REGISTER_CLAIM_FILE_HOOK_V2.
	(ld_plugin_object_p): Take second argument.
	(bfd_link_plugin_object_p): Update call to ld_plugin_object_p.
	(register_ld_plugin_object_p): Update argument prototype.
	(bfd_plugin_object_p): Update call to ld_plugin_object_p.
	* plugin.h (register_ld_plugin_object_p): Update argument
	prototype.

	include/
	* plugin.api.h (ld_plugin_claim_file_handler_v2)
	(ld_plugin_register_claim_file_v2)
	(LDPT_REGISTER_CLAIM_FILE_HOOK_V2): New.
	(struct ld_plugin_tv): Add tv_register_claim_file_v2.

	ld/
	* plugin.c (struct plugin): Add claim_file_handler_v2.
	(LDPT_REGISTER_CLAIM_FILE_HOOK_V2): New.
	(plugin_object_p): Add second argument.  Update call to
	plugin_call_claim_file.
	(register_claim_file_v2): New.
	(set_tv_header): Handle LDPT_REGISTER_CLAIM_FILE_HOOK_V2.
	(plugin_call_claim_file): Add argument known_used.
	(plugin_maybe_claim): Update call to plugin_object_p.
	* testplug.c, testplug2.c, testplug3.c, testplug4.c: Handle
	LDPT_REGISTER_CLAIM_FILE_HOOK_V2.
	* testsuite/ld-plugin/plugin-1.d, testsuite/ld-plugin/plugin-10.d,
	testsuite/ld-plugin/plugin-11.d, testsuite/ld-plugin/plugin-13.d,
	testsuite/ld-plugin/plugin-14.d, testsuite/ld-plugin/plugin-15.d,
	testsuite/ld-plugin/plugin-16.d, testsuite/ld-plugin/plugin-17.d,
	testsuite/ld-plugin/plugin-18.d, testsuite/ld-plugin/plugin-19.d,
	testsuite/ld-plugin/plugin-2.d, testsuite/ld-plugin/plugin-26.d,
	testsuite/ld-plugin/plugin-3.d, testsuite/ld-plugin/plugin-30.d,
	testsuite/ld-plugin/plugin-4.d, testsuite/ld-plugin/plugin-5.d,
	testsuite/ld-plugin/plugin-6.d, testsuite/ld-plugin/plugin-7.d,
	testsuite/ld-plugin/plugin-8.d, testsuite/ld-plugin/plugin-9.d:
	Update test expectations.

2 files changed, 21 insertions, 6 deletions

diff --git a/bfd/plugin.c b/bfd/plugin.c
index 66d286a..b798d34 100644
--- a/bfd/plugin.c
+++ b/bfd/plugin.c
@@ -129,6 +129,7 @@ struct plugin_list_entry
 {
   /* These must be initialized for each IR object with LTO wrapper.  */
   ld_plugin_claim_file_handler claim_file;
+  ld_plugin_claim_file_handler_v2 claim_file_v2;
   ld_plugin_all_symbols_read_handler all_symbols_read;
   ld_plugin_all_symbols_read_handler cleanup_handler;
   bool has_symbol_type;
@@ -159,6 +160,16 @@ register_claim_file (ld_plugin_claim_file_handler handler)
   return LDPS_OK;
 }
 
+
+/* Register a claim-file handler, version 2. */
+
+static enum ld_plugin_status
+register_claim_file_v2 (ld_plugin_claim_file_handler_v2 handler)
+{
+  current_plugin->claim_file_v2 = handler;
+  return LDPS_OK;
+}
+
 static enum ld_plugin_status
 add_symbols (void * handle,
 	     int nsyms,
@@ -337,7 +348,7 @@ try_load_plugin (const char *pname,
 		 bool build_list_p)
 {
   void *plugin_handle;
-  struct ld_plugin_tv tv[5];
+  struct ld_plugin_tv tv[6];
   int i;
   ld_plugin_onload onload;
   enum ld_plugin_status status;
@@ -403,6 +414,10 @@ try_load_plugin (const char *pname,
   tv[i].tv_u.tv_register_claim_file = register_claim_file;
 
   ++i;
+  tv[i].tv_tag = LDPT_REGISTER_CLAIM_FILE_HOOK_V2;
+  tv[i].tv_u.tv_register_claim_file_v2 = register_claim_file_v2;
+
+  ++i;
   tv[i].tv_tag = LDPT_ADD_SYMBOLS;
   tv[i].tv_u.tv_add_symbols = add_symbols;
 
@@ -439,7 +454,7 @@ try_load_plugin (const char *pname,
 /* There may be plugin libraries in lib/bfd-plugins.  */
 static int has_plugin_list = -1;
 
-static bfd_cleanup (*ld_plugin_object_p) (bfd *);
+static bfd_cleanup (*ld_plugin_object_p) (bfd *, bool);
 
 static const char *plugin_name;
 
@@ -463,7 +478,7 @@ bool
 bfd_link_plugin_object_p (bfd *abfd)
 {
   if (ld_plugin_object_p)
-    return ld_plugin_object_p (abfd) != NULL;
+    return ld_plugin_object_p (abfd, false) != NULL;
   return false;
 }
 
@@ -480,7 +495,7 @@ bfd_plugin_target_p (const bfd_target *target)
 /* Register OBJECT_P to be used by bfd_plugin_object_p.  */
 
 void
-register_ld_plugin_object_p (bfd_cleanup (*object_p) (bfd *))
+register_ld_plugin_object_p (bfd_cleanup (*object_p) (bfd *, bool))
 {
   ld_plugin_object_p = object_p;
 }
@@ -572,7 +587,7 @@ static bfd_cleanup
 bfd_plugin_object_p (bfd *abfd)
 {
   if (ld_plugin_object_p)
-    return ld_plugin_object_p (abfd);
+    return ld_plugin_object_p (abfd, false);
 
   if (abfd->plugin_format == bfd_plugin_unknown && !load_plugin (abfd))
     return NULL;
diff --git a/bfd/plugin.h b/bfd/plugin.h
index 8da436a..6a6f0f1 100644
--- a/bfd/plugin.h
+++ b/bfd/plugin.h
@@ -27,7 +27,7 @@ void bfd_plugin_set_plugin (const char *);
 bool bfd_plugin_target_p (const bfd_target *);
 bool bfd_plugin_specified_p (void);
 bool bfd_link_plugin_object_p (bfd *);
-void register_ld_plugin_object_p (bfd_cleanup (*object_p) (bfd *));
+void register_ld_plugin_object_p (bfd_cleanup (*object_p) (bfd *, bool));
 void bfd_plugin_close_file_descriptor (bfd *, int);
 
 typedef struct plugin_data_struct